Implement hybrid include mechanism for C interfacing

src/pystencilssfg/composer/basic_composer.py

@@ -15,6 +15,7 @@ from pystencils import (
 )
 from pystencils.codegen import Kernel
 from pystencils.types import create_type, UserTypeSpec, PsType
+from pystencilssfg.ir import SfgSourceFileType
 
 from ..context import SfgContext, SfgCursor
 from .custom import CustomGenerator
@@ -716,6 +717,10 @@ class SfgFunctionSequencer(SfgFunctionSequencerBase):
     """Sequencer for constructing functions."""
 
     def __call__(self, *args: SequencerArg) -> None:
+        # check if header is in HYBRID mode for c_interfacing enabled
+        if self._cursor.context.c_interfacing:
+            assert isinstance(self._cursor.context.header_file.file_type, SfgSourceFileType.HYBRID_HEADER)
+
         """Populate the function body"""
         tree = make_sequence(*args)
         func = SfgFunction(

src/pystencilssfg/emission/file_printer.py

@@ -42,7 +42,28 @@ class SfgFilePrinter:
         if file.file_type == SfgSourceFileType.HEADER:
             code += "#pragma once\n\n"
 
+        includes = ""
         for header in file.includes:
+            incl = str(header) if header.system_header else f'"{str(header)}"'
+            includes += f"#include {incl}\n"
+
+        if file.file_type == SfgSourceFileType.HYBRID_HEADER:
+            hybrid_includes = ""
+            for header in file.includes:
+                incl = str(header) if header.system_header else f'"{str(header)}"'
+                hybrid_includes += f"#include {incl}\n"
+
+            # include different headers and wrap around guard distinguishing C++/C compilations
+            code += f"""
+            #ifdef __cplusplus\n
+            {includes}
+            #else\n
+            {hybrid_includes}
+            #endif\n"""
+        else:
+            code += includes
+
+        for header in file.hybrid_includes:
             incl = str(header) if header.system_header else f'"{str(header)}"'
             code += f"#include {incl}\n"
 

src/pystencilssfg/generator.py

@@ -85,9 +85,9 @@ class SourceFileGenerator:
 
         from .ir import SfgSourceFile, SfgSourceFileType
 
-        self._header_file = SfgSourceFile(
-            output_files[0].name, SfgSourceFileType.HEADER
-        )
+        header_type = SfgSourceFileType.HYBRID_HEADER \
+            if self._c_interfacing else SfgSourceFileType.HEADER
+        self._header_file = SfgSourceFile(output_files[0].name, header_type)
         self._impl_file: SfgSourceFile | None
 
         if self._header_only:
@@ -164,6 +164,22 @@ class SourceFileGenerator:
         )
         self._header_file.includes.sort(key=self._include_sort_key)
 
+        if self._c_interfacing:
+            # from: https://en.cppreference.com/w/cpp/header
+            c_compatibility_headers = [
+                "<cassert", "<cctype>", "<cerrno>", "<cfenv>", "<cfloat>",
+                "<cinttypes>", "<climits>", "<clocale>", "<cmath>",
+                "<csetjmp>", "<csignal>", "<cstdarg>", "<cstddef>", "<cstdint>",
+                "<cstdio>", "<cstdlib>", "<cstring>", "<ctime>", "<cuchar>",
+                "<cwchar>", "<cwctype>"
+            ]
+
+            for inc in self._header_file.includes:
+                if inc.system_header and inc.__str__() in c_compatibility_headers:
+                    c_header = inc.__str__().replace("<c", "<")
+                    self._header_file.hybrid_includes += HeaderFile(
+                        c_header, system_header=True)
+
         if self._impl_file is not None:
             impl_includes = collect_includes(self._impl_file)
             #   If some header is already included by the generated header file, do not duplicate that inclusion

src/pystencilssfg/ir/syntax.py

@@ -181,6 +181,7 @@ SfgNamespaceElement = (
 
 class SfgSourceFileType(Enum):
     HEADER = auto()
+    HYBRID_HEADER = auto()
     TRANSLATION_UNIT = auto()
 
 
@@ -200,6 +201,7 @@ class SfgSourceFile:
         self._file_type: SfgSourceFileType = file_type
         self._prelude: str | None = prelude
         self._includes: list[HeaderFile] = []
+        self._hybrid_includes: list[HeaderFile] = []
         self._elements: list[SfgNamespaceElement] = []
 
     @property
@@ -230,6 +232,15 @@ class SfgSourceFile:
     def includes(self, incl: Iterable[HeaderFile]):
         self._includes = list(incl)
 
+    @property
+    def hybrid_includes(self) -> list[HeaderFile]:
+        """Sequence of header files to be included at the top of this file"""
+        return self._hybrid_includes
+
+    @hybrid_includes.setter
+    def hybrid_includes(self, incl: Iterable[HeaderFile]):
+        self._hybrid_includes = list(incl)
+
     @property
     def elements(self) -> list[SfgNamespaceElement]:
         """Sequence of source elements comprising the body of this file"""

src/pystencilssfg/lang/expressions.py

@@ -483,7 +483,7 @@ def includes(obj: ExprLike | PsType) -> set[HeaderFile]:
         case PsType():
             headers = set(HeaderFile.parse(h) for h in obj.required_headers)
             if isinstance(obj, PsIntegerType):
-                headers.add(HeaderFile.parse("<cstdint>"))  # TODO: switch for stdint.h
+                headers.add(HeaderFile.parse("<cstdint>"))
             return headers
 
         case SfgVar(_, dtype):